<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>

        .container {
            width: 960px;
            margin-left: auto;
            margin-right: auto;

            border: 1px solid;
        }
    </style>
</head>
<body>

<div class="container">

<!--    栅格系统 -->

     <div class="row">
         12/24
         <div class="col-4">col-4</div>
         <div class="col-4">col-4</div>
         <div class="col-4">col-4</div>
     </div>

</div>

</body>
</html>